Influence of aerodynamic forces in ice shedding

Scavuzzo, R. J.; Chu, M. L.; Ananthaswamy, V.

doi:10.2514/3.46525

Cited by 24 publications

(10 citation statements)

References 5 publications

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“…Those values are comparable with previous experimentation on impact ice 10,14,16 , and indicate that testing was well performed. In general, ice shedding on SRB requires lower shear stress than on CAT beams.…”

Section: B Srbsupporting

confidence: 89%

“…During the tests, for the icing conditions tested, the ice grew linearly along the blades until shedding occurred. The shedding shear stress at the leading edge interface is calculated by assuming that the lift and drag forces are negligible, as well as the flexion and vibration forces compared to centrifugal force; therefore; the balance force on the shedding ice piece depends only on the centrifugal, cohesive and adhesive forces 10,14 . These forces are calculated assuming than the ice accretion crosssection of the detached ice deposit is trapezoidal.…”

Section: B Srbmentioning

confidence: 99%

See 1 more Smart Citation

Icephobic Coating Evaluation for Aerospace Application

Laforte

Blackburn

Perron

et al. 2014

55th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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This paper presents an extended study on the properties of icephobic coatings for aerospace applications, more specifically rotorcraft. Ideally, an icephobic material should be the least expensive anti-icing solution, inasmuch as the anti-icing effect is not destroyed by inclement environmental conditions. Several studies on the subject have already been published. Nevertheless, in most cases, only the results of ice adhesion on freshly coated samples are presented and discussed. In this study, the effects of aging (weathering and erosion) and of the number of ice/deicing cycles on coating durability were also considered relative to their possible use on airplanes and helicopters. In the first step, ice adhesion was measured in Centrifuge Adhesion Tests (CAT) on eight promising coatings. The ice adhesion τ adh of the candidate coatings was found to vary from 0.001 MPa to 0.16 MPa. In the second step, in order to analyze ice accretion and ice shedding, four favorable coatings were evaluated in a wind tunnel on scaled-down rotor (SRB) set-ups, which were iced and rotated until shedding occurred. Regarding the environmental aspect, the durability of the utmost ice adhesion reducer coatings was evaluated under rain and sand erosion, as well as multiple icing/deicing exposures. NomenclatureA = Area of the adherent interface (mm 2 ) AMIL = Anti-Icing Material International Laboratory BHTI = Bell Helicopter Textron Inc. CA = Contact Angle F = Centrifugal Force (N) hp = Horsepower ISO = International Standard Organization for Standardization IWT = Icing Wind Tunnel m ice = Mass of the ice samples (kg) NRC = National Research Council of Canada r = Radius of the beam at ice coupon position (m) SD = Standard Deviation SRB = Spinning Rotor Blade USAF = United States Air Force τ = Adhesive shear stress (MPa) ω = Radial speed of rotation (2π RPM/60) (rad/s) * Associate Professor, Applied Sciences Faculty, 555 blv. Université, Chicoutimi, AIAA Member. † Project Engineer, Applied Sciences Faculty, 555 blv. Université, Chicoutimi. ‡ Professor, Applied Sciences Faculty, 555 blv. Université, Chicoutimi. § Staff Engineer, Flight Technology, 600 E Hurst blv. Hurst, Senior Member. Downloaded by UNIVERSITY OF NEW SOUTH WALES on July 29, 2015 | http://arc.aiaa.org |

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Section: B Srbsupporting

confidence: 89%

Section: B Srbmentioning

confidence: 99%

Icephobic Coating Evaluation for Aerospace Application

Laforte

Blackburn

Perron

et al. 2014

55th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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show abstract

“…Applying the same procedure on filtered test data (in blue) as on rough test data (in red), the ice mass expressed from rough test data as a function of angular speed in RPM ( Figure 10 (12) The power factor obtained for the shear stress decreases: for the CAT tests it was 1.55, as compared to 1.25 for the CAT-NG tests.…”

Section: All Testsmentioning

confidence: 94%

Centrifuge Adhesion Test to Evaluate Icephobic Coatings

Fortin

Beisswenger

Perron

2010

AIAA Atmospheric and Space Environments Conference

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Ice accumulation is a human safety risk and a cause of important material damages in maritime, ground and air transportation, on ground and maritime energy exploitation and in telecommunication and electric networks. Many ice protection systems have been developed to prevent ice formation, but they are expensive to use due to their energy consumption. Passive systems, such as icephobic coatings applied on exposed surfaces, appear to be an interesting solution to prevent ice accumulation by reducing its adherence; but coating icephobicity is difficult to quantify. To measure icephobicity, the Anti-icing Material International Laboratory (AMIL) developed the Centrifuge Adhesion Test (CAT) in 2006. The test involves icing the extremity of small beams under freezing drizzle in a climatic chamber. Following icing, the beams are balanced in a centrifuge and rotated at an accelerating speed until the ice detaches and the corresponding rotation speed is measured. The adhesion shear stress is calculated from the centrifugal force evaluated at the detachment rotation speed, and the ice contact surface. The results are then reported as an Adhesion Reduction Factor (ARF) which is the ratio of the adhesion shear stress of the beams with a candidate coating with respect to uncoated beams. The higher the ARF, the more icephobic the coating; values below one indicate an increase in adhesion. For coatings with high icephobicity, the CAT apparatus sensitivity proved to be insufficient to evaluate the ARF. To remedy this, in 2009, AMIL modified the CAT apparatus to increase its sensitivity. The new CAT, called CAT-NG, can measure ARF in a range of 0.6 to 1 000 inexpensively and timely. To ensure reliable ARF factor with confidence level of 95%, the beam area exposed to icing is polished after 5 tests, or every month, to reduce the ice erosion effect on aluminum surface. Also, the ice specimen mass should be 5.5 g ± 5% with a length of 34 mm ± 5%. For glaze ice tested at -10ºC on 6061-T6 aluminum with AMIL Standard Surface roughness of 0.7 µm, the detachment speed is 7 800 RPM ± 7% when the beam is rotated at speeds increasing linearly at rate of 300 RPM/s corresponding to a shear stress of 0.51 MPa ± 7%. NomenclatureA = Area iced m² ARF = Adhesion Reduction Factor E ice = Ice Young Modulus Pa F = Centrifugal force N l beam = Beam length m l ice = Ice length in contact with substrate m m ice = Ice mass kg r = Beam radius m w beam = Beam width m Ω = Angular speed rad/s ε = Strain τ = Shear stress Pa τ bare = Average shear stress measured on 3 simultaneously iced bare beams Pa τ coated = Average shear stress measured on 3 simultaneously iced icephobic coating Pa

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“…Once the piece of ice breaks up, it simply leaves the computational domain and no calculation of its trajectory is done. Stresses in accreted ice caused by aerodynamic forces have been studied by Scavuzzo et al 6 and an ice failure criterion, Labeas et al, 7 based on both normal and shear interface stresses has been used in a finite elements code to simulate the electro-impulse de-icing process of aircraft wings.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Ice Chunk Trajectory Using Proper Orthogonal Decomposition

Yapalparvi

Beaugendre

Morency

2012

4th AIAA Atmospheric and Space Environments Conference

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In this work, calculation of trajectories of ice chunk are carried out at varying values of ratio of density of ice piece to that of the ambient fluid. Proper Orthogonal Decomposition with Interpolation (PODI) method is then applied on snapshots of trajectories simulated by computational fluid dynamics. Snapshots of trajectories are obtained based on cartesian grids, penalization, and level sets. The extracted POD modes from snapshots are then used to reconstruct solutions and capabilities of POD with interpolation are demonstrated on ice trajectory calculations for flow around iced airfoil and cylinder for density ratio's that are not part of the snapshot set.

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Influence of aerodynamic forces in ice shedding

Cited by 24 publications

References 5 publications

Icephobic Coating Evaluation for Aerospace Application

Icephobic Coating Evaluation for Aerospace Application

Centrifuge Adhesion Test to Evaluate Icephobic Coatings

Calculation of Ice Chunk Trajectory Using Proper Orthogonal Decomposition

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